One challenge could be protecting the baby from their enemies. Vegeta has made many foes over the years, and they might target the baby. Also, Vegeta's Saiyan nature might make him push the baby too hard in training, while Bulma wants a more relaxed approach. This difference in parenting styles could cause some friction between them.
As far as I know, no. The idea of 'baby bra' in relation to Vegeta and Bulma seems rather unusual. In the world of Vegeta and Bulma fanfiction, popular stories usually center around things like Vegeta's training, Bulma's inventions, and their family dynamic with Trunks. There's not much indication that a 'baby bra' fanfiction would be well - known.
There is a fanfiction called 'Baby Vegeta's Training'. In this, it details how baby Vegeta, despite his small size, still tries to train and become stronger. It's interesting as it gives insights into his character and his unwavering determination to be the best, even as a baby.
One possible plot could be Vegeta training with baby Bulla. He could be teaching her the basics of combat in a gentle yet firm way. For example, showing her how to throw a proper punch or dodge an attack. He might also tell her stories about their Saiyan heritage during breaks in the training.
The theme of Saiyan heritage also frequently appears. Since both are Saiyans, fanfictions may explore how their Saiyan nature affects their relationship. For instance, their shared instinct for battle and their connection to Saiyan traditions can be central to the plot.
Perhaps Vegeta Jr could challenge Vegeta to a sparring match. Vegeta, being the proud warrior he is, would accept. During the fight, Vegeta Jr might display some new techniques he's developed, which could both surprise and intrigue Vegeta. And in the end, they could form a stronger bond as they realize they share the same values and goals as Saiyans.
Since we should avoid the 'lemon' aspect which is often not appropriate, in general Vegeta is usually depicted as a strong and proud character. He might be shown as a mentor - like figure to Pan in fanfiction. Pan, on the other hand, is often a curious and energetic character. In non - inappropriate fanfictions, their relationship could be one of mutual respect and growth, with Pan looking up to Vegeta for his power and experience.
One potential theme could be family. Vegeta's relationship with his son is explored, showing how a Saiyan warrior like him can adapt to fatherhood. Another theme might be growth, as Baby Trunks learns from Vegeta and Vegeta also grows as a person through this new connection.
Well, it could be that Vegeta, upon meeting Baby Trunks, realizes the importance of family in a new way. He might start to see the future differently, knowing that he has a son to protect and guide. There could also be some cute moments where Baby Trunks tries to imitate Vegeta's tough guy expressions, which would be quite endearing.
In this fanfiction, the baby might be a key to uniting different factions in the Dragon Ball universe. Since Vegeta has his Saiyan heritage and Bulma is an Earthling, their baby could symbolize a new era of peace and cooperation. The story could show how the baby grows up being adored by all the Z - fighters. Vegeta would be protective and train the baby in secret, while Bulma would be showing off the baby's cute side to her friends. There could also be some comical moments when the baby's Saiyan appetite clashes with Bulma's attempts to feed it a balanced diet.